Cynikal 

All,

I'm about to take on my first disk brake fork build and have a question. I have been waiting for Nova to restock their disk specific fork blade but that is taking a while. My question is, can I use a normal fork blade if I plan to use the "Willits" style brake mount? I have heard this in passing but wanted to check in with the more experienced builders here. Thanks

unterhausen

I should have bought some when they had them in stock earlier this year. I'm tempted to get a set of the lightweight Reynolds blades

The Willits style mount on a regular blade doesn't fill me with confidence. I know there are experienced builders that build lighter disc forks, but it's not worth it for me. Have also seen experienced builders that build disc forks that folded

Andrew R Stewart 

I'll have on road/trail experience in a few months. I'm building a path bike and use a touring weight fork blades (forget the specs right now) with a Willits replica mount. Andy

unterhausen

Are these recent vintage? Your post surprises me somewhat since you have advocated against using .7/.4/.7 frame tubes, which seems less failure prone than using non-disc specific fork blades for disc forks

Andrew R Stewart 

Eric- Yes this is not my usual cautious choice I gave this a lot of thought and have some Nova disk blades on had but I wanted a lighter and less stiff fork than the last one I made with the same crown and the Nova blades. The few images of "failed" forks I've seen that used common road bike blades had the bending right above the upper caliper mount, all with a minimal mount that didn't run up the blade's back side (like the Willits does). Will my choice prove to be OK or not? I'll find out. I've watched my forks deflect rearward on my loaded touring bike (cantis) about a half inch and am interested if I see this on the new path bike this fork is for. Would I suggest others to do this, no. Andy

Cynikal 

I'm now leaning toward using this set of blades. They use a thicker blade (1.1) for the disk blade and a thinner blade for the other side. I wonder if these would meet you need as well?

https://www.bikefabsupply.com/fork-b...m-length-gdrms

Andrew R Stewart 

I thought about using two different blades, disk specific on the caliper side and "standard" on the right side. This is what we did for a couple of customers when I worked at Cyclery North and wanted to have a fork stiffer than one with SL blades (Columbus was most of what we built with) but not as heavy as a SP fork. I would strongly suggest that your caliper mount extend up the blade even with the added wall thickness.

What stopped me for this fork was the big difference in tip diameters, and the tapering down towards the tip. One aspect of the Nova blades is that they are 17mm at the tip and thus their bending resistance is greater than more classic blades with their 12/13mm diameters. But I really didn't want blades that didn't match each other and have dropout treatments different too.

For the fork I made I trimmed as much of the tapered ends off as I could, made my own drop outs (facing slightly forward instead of just down) and ended up with the caliper mount tang right about where the blade stops tapering. I'll be posting a thread of this frame/fork after I do something about the finish (which for now will be a cheap rattle can job as to make stripping and refinishing at a later date easier). Andy

duanedr 

Steve Garro did a fork with different blades on each side and then added a rib up the backside of the standard blade to stiffen it and reduce the difference. No idea if it helped or if there was a problem to begin with. It's an interesting idea.

unterhausen

I'm glad bfs has disc blades now. I suppose I should get some since I asked about them. I'm not sure you're going to notice having 2 different blades. Just don't get them mixed up. I doubt those would bend equally.

The thing about disc forks is that steel is a bit marginal for this application. If you build too light it might work for someone and not work for someone else. I would definitely be the "someone else."

The second worst part about the unavailable Nova blades is that they were so cheap. I probably wouldn't blink at paying what the Reynods cost if it weren't for the fact they are 2-3 times the price. It's nice that you can get them already bent though.

Trakhak

On using fork blades of different gauges: they'd almost certainly exhibit two different rates of response to road shock. The effect would likely be subtle, but it would bother me.

In fact, my all-time favorite bike is a Specialized Langster fixed-gear bike from the first year of production - oversize aluminum frame tubing, oversize straight-blade aluminum fork. Every time I start a ride on that bike, I'm reminded again of how blissful it is to ride a bike whose wheels track perfectly. A steel fork built with one light-gauge fork blade and one heavy-gauge blade would drive me insane.

unterhausen

If you didn't know about it, you probably wouldn't notice. If you did know about it, it would drive you crazy. Most of the deflection is at the top of the blade, and they are the same there.

Cynikal 

I think you are correct for that being important with a thin, high pressure tire like a track bike. This will be a gravel/light tourer build with 42-48 mm 650b tires or 40mm 700's. That's a lot of tire to dampen most of the feedback from a frame.

guy153

It probably doesn't make any difference in practice but I don't really like the idea of one blade flexing more than the other while riding. It would cause the front wheel to roll to one side and possibly to yaw a bit as well as you went over bumps.

Andrew R Stewart 

And there are many thousands of forks with vastly different blades, suspension forks that often have one blade sprung and the other damped. Andy

unterhausen

After this discussion, I definitely have to get some of those blades. But the sad fact is any sort of subtlety like this is lost on me.